The West Highland Line Alex MacDonald is a softly spoken railway man, and a true Highland gentleman. From up on the footplate of his clanking, hissing beast of a Black Five locomotive, he waves us aboard. “Surely I have,” he says, when asked if he has a minute or two to talk. “Shunting can wait.” And while we discuss the season ahead, whether he’s ever run out of steam, and what that big lever does, he still has time to greet a succession of small boys lifted up by their parents to peer into his cab. It is as if they are being blessed by the Pope.

“The Pope?” echoes fireman Neil Henderson, fresh from shovelling two tons of coal, and ready to shovel two more on the return journey. “Never mind the Pope! For us, he has the rank of God and above.”

Alex looks slightly embarrassed, but the radio crackles and spares his blushes. It is time, he announces, to shunt the coaches clear of the arrival platform; in other words, time for those of us whose journey has ended to climb out into the thick wet mist of the fishing port of Mallaig.

I have always liked trains, and once upon a time I could have been one of those boys lifted up from a Highland platform for an engine driver’s benediction. It is a fascination that dates back to my first decade of holidaymaking, to the long trek back to the Isle of Skye – my mother’s place of origin – on the overnight sleeper, a small boy so excited that sleep was the last thing I wanted to do. Which is why I find myself momentarily watery-eyed; it is as if I have travelled back 45 years.

But this journey had begun a mere 16 hours earlier, in a very different setting. The Caledonian Sleeper to Fort William sets out every evening from London Euston. Once passengers are on board, the long-haul destination produces an instant camaraderie, and people begin to gather in the lounge car in an interesting cross-section that ranges from a beaming American family, heading for a wet week of ancestor-hunting, to a half-mooned lawyer type with a share in a Highland estate. Stories are swapped and whiskies are distributed by a doggedly chipper bar steward who has the look of someone who knows he has got a late night ahead.

I slip away when conversation reaches the subject of Scottish independence, and minutes later am tucked between clean sheets, hurtling through a nation at rest.

The next thing I know, the train has worked its overnight magic, and the canyons of office blocks and black cabs have been replaced by red deer grazing on granite crags. This is the West Highland Line (Glasgow to Fort William and thence to Mallaig), the most beautiful railway route in Britain. My cabin attendant brings breakfast as we emerge onto the 56-squaremile wilderness that is Rannoch Moor, a raging sea of bog and rock that only the railway dares to cross. The track-layers had to contend with horrendous conditions back in 1894, and 37 of them died. In places, the ground was so boggy the line had to be laid on a floating raft of logs, where it is still ironed flat by passing trains.

Arriving at the more man-made landscape of Fort William, it is time to transfer to the next leg of my journey. The Jacobite is a daily steam-hauled service that has recently achieved a new kind of stardom as the Hogwarts Express in the Harry Potter films, in which it steams majestically, just as now, across the Glenfinnan Viaduct.

As we cross the snaking, single-track bridge there is a glimpse of Loch Shiel, and of the monument that marks the spot where Bonnie Prince Charlie first assembled his Jacobite army that nearly did so well for the Scots. His hopes ended with a catastrophic defeat at the Battle of Culloden, and he had to flee over the sea to Skye, and eventually back to France.

Beyond Glenfinnan, the train climbs through forests of ash, carpeted in a tartan of bluebells and bracken. The peaks are hung with the fraying rope of streams in spate and the lochs look like slices of sky fallen to the ground. Trailing clouds of steam, The Jacobite clatters through this mythical landscape, breathing hard.

Then we round a corner and a door is thrown open to the sea. Suddenly, there is a view of islands out across the Sound of Arisaig, where Eigg, Rum and Muck crowd the horizon. Beyond Arisaig lie beaches, and water that’s an otherworldly Caribbean blue. And then there is Mallaig, with the Isle of Skye in the distance, and there’s me on the rain-soaked platform at the end of my journey, both past and present, then and now.

Further information Your journey on the Caledonian Sleeper starts in London, ends in Fort William and takes 12 hours (from £60 one way for a berth).

From Fort William you take the Jacobite to Mallaig, a journey lasting two hours (from £26).

The Bernina Express It is no easy matter running trains in one of the steepest, most topographically awkward nations on the planet, but the Swiss seem to take it in their stride. You name it, they have run a railway up it, by hook or by crook, by rack or by pinion and by Albula and St Moritz. Those last two are key locations for one of the country’s most spectacular trains, the Bernina Express, which clings to the side of the mountains like a lonely goatherd, before eventually breasting the highest railway crossing of the Alps and continuing down the other side into the intoxicating pastoral world of northern Italy.

The red flash of the brightly painted train is absolutely unmissable among the gentle greens, greys and blues of the mountains. Its journey begins as it departs from the platform at Chur, the oldest town in Switzerland, where it makes a modest start alongside the baby Rhine and continues into the lower part of the Albula valley. But the Albula steepens quickly, and the river disappears into a dramatic ravine, forcing the train to criss-cross the gorge, creaking like a sailing ship in a full-bellied wind.

Uphill of the Alpine village of Bergün, the Bernina ties itself in knots as it negotiates a piece of engineering that has been recognised by Unesco, plunging repeatedly into the mountainside, completing slow, disembowelling circles in the darkness before emerging into daylight once again.

Ospizio is the highest point on the track, in an ethereal landscape scattered with strangely lucent meltwater lakes. These shining pools are the header tanks for a river system that now starts to descend into Italy, eventually to Lake Como, way down below. The railway, too, starts to descend rapidly, repeating its routine of hairpin turns, before entering a world of meadows, orchards and vineyards. Its final flourish before the end-station of Tirano is the viaduct at Brusio, which looks like two-thirds of a steeply banked colosseum as it delivers the train gently to the ground.

The Orient-ExpressThe Venice Simplon Orient-Express (VSOE) is a train of unmatchable pedigree, with a legacy of appearances in films and novels, and a history that spans two world wars. Its heyday was the Golden Age of rail travel, during the first half of the 20th century, when royals and heads of state, writers and even spies would set out for the furthest corners of Europe, travelling in supreme style. Back then, the Orient-Express ran to Istanbul, but today’s VSOE sticks largely to a bread-and-butter route between London, Paris and Venice – a journey that lasts 31 hours.

This is no ersatz reconstruction. The carriages are the real deal, most of them dating back to the 1920s and 1930s, and lovingly restored. London-origin passengers board the umber-and-cream British Pullman to rumble down through the Garden of England before transferring to the rake of navy-blue Wagons-Lits that are drawn up alongside the platform at Calais, each with its own crest and polished metal lettering.

Inside, the wood-panelled cabins are covered in marquetry, with floral motifs delicately crafted from polished veneers of boxwood, sycamore and walnut. The dining cars are decorated with opalescent Lalique glass panels of sculpted small-breasted nymphs with bunches of grapes. The chairs are upholstered in velvet and the tables are glittering with Limoges china and crystal wine glasses. Dinner – four courses, fine French cuisine – is a big event, with everyone gathering in the piano bar beforehand, elegantly dressed.

Breakfast next morning is served in the cabin, while the train ploughs across valley bottoms like a slicer, drawing its handsome blue blade across rivers and orchards, before clambering up through the foothills of the Alps. Lunch comes with the last of the long Alpine tunnels and the beginning of a descent through the vineyards of Italy and, ultimately, down to the lowlands again, then out to the lagoon and finally to Venice.

Oslo to BergenThe 308-mile feat of engineering that crosses Norway’s rugged spine, linking the capital of Oslo to the coastal city of Bergen, gateway to the fjords, took some 150,000 men 34 years to complete (in 1909). It is a journey that really merits two attempts, in winter and in summer, to fully appreciate quite what they achieved.

The Bergensbanen train climbs up to a 1,200-metre plateau that is almost as high as Ben Nevis, so in winter it fills up with cheerful skiers, seemingly unconcerned by how inhospitable the landscape becomes on the other side of the window as the caterpillar of carriages makes its ascent. The stations are draped in icicles as long as your arm and the landscape becomes a blanket of white out of which emerge skidoos and dog sleds, but the Bergensbanen moves through it all unconcerned; in Norway there’s no such thing as the wrong kind of snow. Geilo, about midway through the journey, at 800 metres altitude, is one of the country’s biggest ski resorts.

The summer journey is a complete contrast. It begins in pleasant agricultural land, but the greenery soon loses ground to gneiss in varying shades of grey as the train climbs onto the barren, rocky, desolate Hardervigga plateau above, where bikers and hikers have taken the place of wintersporters.

You know instinctively once the train has passed the highest point because it starts to descend into a new, more humid, milder coastal climate, and suddenly there are waterfalls and forests all around. At Myrdal a lot of travellers change trains onto the Flåm Railway for the spectacular ride down to the Aurlandsfjorden, on one of the world’s steepest tracks. But the Bergensbanen has its fair share of dramatic scenery, too, as it descends to sea level, and scythes along the edge of beautiful, mirror-calm, mountain-lined fjords to finally reach Bergen.